SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '51e5bedf6b56df9629cf3406d354f2495df8b15fc6e07e60ebb86b102d38965a' 
  AND token = 'NSf6TL4BQd8I1B9/Z/l1wmSXKYooi8UO8lw/vfqk4fU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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