SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b05ddf54faabd68f4bf7fbc0661b7e8a15c79f929aaad40ff3f235f51b8cd95' 
  AND token = 'MV+kJ8nbKPvOjAKbsSb2hQtGCe1033C3iZ72EYL1TgU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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