SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'be4697d820f214a1a60ca740665238f0dee1fefff3435482d9c32cdf5bdfa3c2' 
  AND token = 'vrMBdLUMdzGm2X+nWLjjItmg1vsZ5lTZ7f6B2Yo25Pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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