SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9baa213a1fed76a41081cb667a42b92c6f504f2d12603fb555d0a1ea32840fc' 
  AND token = '+jY5wPQWBwSvimqrsFsfNNTMIY/DcZd8uIrRp58Wa9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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