SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3f7c08a37cb664783fa6bc4c0cd9e46c2beba61816cb14565e49f4bb2d49e19a' 
  AND token = 'Ho0ZE7m+8WBmq95QXGVZFe96upi8Sqos49lRlRxJgrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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