SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '208bfa48b9cdc3e369d8adcae13555b384d863ed218e3d3e57aff893c4a54464' 
  AND token = 'kI1aEAHAmGTZKwmti3cNL6HRryukPFhXwpFFy7leK3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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