SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f99399e86d6da2723972e7a30a94f79cc06ed3fd341b442b298b84079734e02' 
  AND token = 'KhPYTzvcyl0/pXaQANyi5ZBcSH6UknEpwQSpV4QTcdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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