SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee84e83454457ed8a023823a303b4ea06808fe878804db5e751cc18f88047467' 
  AND token = 'iHwkGxQiuklJbNK90vhc18unPx/G5ffsNTbaqNUZszo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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