SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f5438f541e7e1986bfe0dbd2b72dad26db1c8bda2731c11e64c2f1c6ee6a9ee' 
  AND token = 'oaNj7brBxfDR6yfuoPZSu5s06iSD0JD+KNXTSG5O2D8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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