SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bd4e15e77f3400723aa8e6aa8c552906db8ee617765abff9f90ae6f82a3eeeb' 
  AND token = '/hd/6K1IkU56QqbZTWOHtop6eirGhjxzzudWNMCJBpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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