SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'aa28cd340456a53583d8c0cf07a32f890c76b4fce2a46b169eb3de12e798d5cb' 
  AND token = '0VWBfQmYvueR2nwcy27uMDL/7nAmgCuKNRfmrZ2b+oE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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