SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a640ca014812d0cda8529bd9cbd28a24fb86be3d996a455f453caf260cbc5b' 
  AND token = '30viUFK0gKXJbG0QyVif2uGuDPIjW1mY1y9hJ+Vpl1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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