SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '658f08a7c24f5ac4ecbf53a46ce56760816744204f31b5029489c979904151fc' 
  AND token = 'Rjj3rw7NsKg5CrUddxgrs8P+Amhn13SYqvxBF0b+MNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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