SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2a85a916b8a73e89bc95a3f962fe2cb30757fb35e488b38b2195917c14eba4d' 
  AND token = 'cpqAhL1kBgB28c3AuDUmaxL59uKa6cQget3i+44fLqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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