SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3008596079ad01dd3b921429f6806157757464e03cddf20fea4f1ed56b184759' 
  AND token = '5aw+jPJVX3AvZ4gSeh3gwYwPp5hPa5vhNhnTKI/fUWk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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