SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a4a657392f64f921e93759cedfcd48687c04a457f52bc8344d44e5438cddf4d6' 
  AND token = 'd27HffAE72j3QekDdZkyIziynmRd6NB9Op84ix85LOY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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