SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9ddb16107df519122b5077b71038c22c5bdf64dd2cf8a2d80c181290dabf41a' 
  AND token = 'omY6DA5OGxYYT2QKU+iF1ustJoDRrM0MF/9rOuLWbpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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