SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a452009988bd11e3e827881887de88b0ab92e88d60cf80bffa3a999e840e546f' 
  AND token = 'MvsJ7tLtY2jI6XVzf/ESjqg4hwVhbkJTMMV3SSHkbCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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