SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bb671873f6a27aa77b6258c0db5262dd1c3b3733d3586fea7ab2375460cd4f50' 
  AND token = '8M8pJkH1Lo7au1zkV8mEFGy80jJNi9HjnHjWJwxO55w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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