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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b49d6f2e3354295a4daf727558583e8d88b4c20711264c91b74c0943c8d96dbb' 
  AND token = 'xQr8ZZmB/NA6eaBA1PWVQBAUbid+uZnpdS4eRfIMyOU=' 
  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"
    }
  }
}