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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5341d8350d9e6f8dfcc9d407a29f57dfb551a289021d8783434b9603695fcc4' 
  AND token = 'n83x8kN7RHO9mn3+h1P90PRVt0MSepsXFqIYYzBLe9g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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