SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b74a263518f9e8e1e67988356eaabe91ac25755639fda88b7991764cda7c39d9' 
  AND token = 'MlXPoe7Zhz90dJJnWUl/hWbijYL+N29kMfwcxdHIgEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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