SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47757775fc32588875d56b28a9d6c10dbf9f61bdfa930d80afd928a04739c265' 
  AND token = 'cowS83cCZsrApp45/WRbHfCARIjWb2OlwUGRj8b4nX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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