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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c83480f4d6e4deddd62327a3d25dfb9907af73fdda4ecc0f47aa0625c657f9b' 
  AND token = 'N9tIq7yQy/hWEXbtfIyTE2SqT4QJ2/AkCoDL9O0BDiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}