SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dba1f75d73103968fde3d63800a55a93680dd2657cab042143cb1f1d4235c3ba' 
  AND token = 'B6hflQ+IJUGbGiVhwYYVG0NX+x41KqyPX/mOSfOLHKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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