SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6197420a14b98347d025a432349c7818f554c24c0b04c998807b1377efda1802' 
  AND token = 'XPLYjHXgOnSoxfckh73bddsi5gnJJPbDX/Yzk2uA3Ww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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