SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '786bf553eca430849d0d8ed8656ffa393959a6906b9c3d21fcc3d0fe12eb6c78' 
  AND token = 'aTDqJFVpiC2JbUWTEAFS6oR0wm40nprxZhLmnqHdKjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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