SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a2b90ce1b2ac64ed793472a91c1864f072dbbbd8b05f0ada735d1e13ea9dfe5' 
  AND token = 'QNgB041j4QODyS5eJwkj2AEgVRh+NUzT6TnHdxCpjro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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