SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '20c3f11d2486425ae7ee4126f718c27bdd48817c511fe40db3f2d1bef9113baf' 
  AND token = 'PzZ1559/jCtur2zBd8xKDVfOf8voOEMr3H+5/zDYfh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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