SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'eff4d57db2df34869f46f16e105ed47cf8b223e66122d78575590a7ba9fddabe' 
  AND token = '28if9tatczdvrB6F0HbUYiMkOnwbNDm1gLpfWaHAPLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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