SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b8f36661de5580a229b1452101cc9996c35b0382bfc2c5b5b8d493b5e0e89d46' 
  AND token = 'r9kgYLiOX1qcOi/EfgqdbLdNy39cLjboG7JrxH6sQCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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