SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fffd23d8238eb05eba5950511e19270c20dd3b9e27d045bb79dec6b942a0c8c2' 
  AND token = 'M5bUajG6Z260ougwJmhL/RJmoWzhNK9/f1rvpduVwj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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