SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3bb0ce1c1c6a82ba7d556923e21a5438fe130dc22a76f44abf6e7deee0696fb' 
  AND token = 'N4vs2nChiqvNJdB9BC1YjX7+2gAyZvouDDmFM9GMxqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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