SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2087d26da88648796a325373f23f21756cca450001c3aec86d1f612d29ecbf8' 
  AND token = 'pKJz/fkY11ke2yU7rzQFtoJr82SFd1wYIrtuYuXUIJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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