SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5f279db1021b49a80adc79bf4d63b5101ad683589f43e44a3b338a8715c343a9' 
  AND token = 'bmDiSV/rRmsOkRy6rCqxhCRuXklX2eWpGwKcAFrX1B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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