SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f688be1c9480eb1efb7de6c638f9f5938a2337d357e0a34005660444c4befb9' 
  AND token = 'tbQKRtBegki44W6PDs3ERryA4sXkey2/eTiP5/H14BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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