SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4a03a150916426b6638701b428f24c9077cc1740b64cbe81d7f13348441355a' 
  AND token = 'fUdmf7BF/fZfpn+s7F2H9JwWZX4XUYNRKjYaGiRc77k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00092

JSON explain

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