SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b9b342188ff089b6b625b5def76a5911a2c28571e9280284d82311657e5a324' 
  AND token = 'evaE+otCydAguFxrOnAvTQUOBMF+5yUywCrTsWP07fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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