SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d11d909c2f6412d05838fd08febfcc1eecd6fc56880a1f72e4639a058a2d7ec' 
  AND token = 'WJ1RfNEInOLT6fHAfTQdbeiUHjMrmQK4xLukDvFJi88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}