SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27d5cddd03cd86d5c1c9d73c72b65af910e4b2d60929aba7782de673dbcdf3d4' 
  AND token = '14YOfezxudi8I/RU/ksvq4pqckbcFMyHoVg08WwBZIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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