SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba61581597c9b1578dcbf8a968c08e93f9fcb4264f7491a2e57f7be9365c3116' 
  AND token = '05b6aOGi42OASSldbvAbFJXe6eASU0YcTdJSmW4S0bE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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