SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b2847319855ec3ab99bf82c39fbd5f41f7c28c7f9310cebd6ef83d616559506' 
  AND token = 'DY+ETjYVWMV52fSgaqilAUB/H6Z4w0+UCqLAME0wizk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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