SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e1e6ed32a5e83221353e0c4cb5216a1b9bce56ea8a25eb577c6cdb2e5ec0114' 
  AND token = 'AssarKtZrhAHcItEbRchtz+kN3WIwk4PU05EzOAdjMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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