SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f68c8881f528322702e022dc108ddf612918d457f966e3f3e051b3be22e11bb' 
  AND token = 'rNl1BriTd+Z/V3cy08xSPa3rQQpKNQ7Enc2Pw2E9e/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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