SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abf4828fdecb1666f65a2555e3e92c67b1f0d64e463c6f17a740b817ed508be7' 
  AND token = 'nwKTpx+NvkXX5xF3cYE5MdQwfKWAgZwUeHX9h8csDhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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