SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15c64993e6691aeb82020c00ad012c6f1a638822eda61220fd47dc5dec80c5eb' 
  AND token = 'LNL0QdM99B9G/jgnUAF0JKf9gr9C35h/ZdjyltQjspg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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