SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cb4c2470331b07fc7e6da56b5df8a0be2c14a738e012461de34ee37b94e2936' 
  AND token = 'y4zdzQWK1+/7LqpgAJa++cHz/pFSFPcwUrOVKmYwI8w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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