SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca6c25a819944d85da034b99c23acc39a94d522bbb7f87e89a4fddee3044af18' 
  AND token = 'hVJVs1whDsqw4R/QHri7mtArLYGcCI7jcwChkzIlGgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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