SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e52281bd7ed2bf4424de13949ed8e2290ccb2677e121d0ac85f0c0e82ea51e3a' 
  AND token = 'cpQk8UD2YeEXw3Jy+4+v9mh/XLs5fbWx/w3F3hzFEiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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