SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7b6b357d4c6ff4f15c86f58556534b8316bb722d7cf874e402df0e8e092f7746' 
  AND token = 'gKLCiyW/tDVOipe/ZoKZKYMHqSsRTk42xOdBvXGA7cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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