SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae410dd00edde8617366c1b5c31024432ce90b82c363d30898f066b9e7b3dda4' 
  AND token = 'opUOMVroVSTgXmjrXKxltPHURE0L6JkB6mZFSH0Qxyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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