SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '508c85c1abc96dccf3eb1a749680b5cc5ccfffbe1054f974f38523e9edebf4e6' 
  AND token = 'O1TqiuBYhFxXO2vcESWmgpQKiCb8YvAVZZoG9Y2hSKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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