SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3485371e392da35c5cdf931b35dee7e8cf530e40b996d363f6fa93e79e75c16c' 
  AND token = 'WLKd5CgBX1Z1oZNyA64TdV/ReWBdyouMmLC+9BwiRG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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