SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c47512b073cddbb77a41220e720bd154040bfe997811f17fdcd16e98f2c0eb3e' 
  AND token = 'gTGBVCvH5jP/Yn3gInvjYZRh2HPLl6TBtyiXgjdUDRo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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