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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e501c625c7c3c3411bfa23bd9dadd8882bca8b90c355c46679db75310f9bbbe2' 
  AND token = 'O0ZcJIDZPa6J2VYfqXBLQfM1WYLUJD+qMF8//Bb6r2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}