SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '594f8118c2be1b34414f9ddf15a5a118eb4e1d0efe550e42dc584ea0d6df08a4' 
  AND token = 'bx7eoCC3129ntGpkwLuXaPJ5Pynvwsm5pG6DWUCOwc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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