SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ace38b4d52082f3244c261c45412d77edd9de6c25f21543aca4adafcef6ff14' 
  AND token = 'B9Zt2kG6243R9AO4xt3J3ezZujrTxsNSag2z25beTEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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