SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66ab49d84a4ecf3785dc2a9db92dd029ff1c1703c6514ecf9d8056249a374d6a' 
  AND token = '6oR5uHm9hhgPfGX31LBp+xvR2QsFbhms1m+6KRZPmXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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