SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '431a28a73aa1f1489a858bf31c66623b5245e168b31268748592ddba353ead11' 
  AND token = '0HnOMWuqoeK8FnWfhH8Ix3bK98jdTNIciBMhoaVLvvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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