SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5fc0e8b43f6dd5cc963e57c2e4bd7eccc987e55025eb26546da3df6a42dd3f5' 
  AND token = 'VjFHL8qndWRPsDjLaIgBb0+3F82xhKMBC7im8QtzMNw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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