SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bced52ec3fdbacb1d2f60b9f06dd6c7330dc0730d21b95c2a342561fcae7de5' 
  AND token = 'Hxe2Yr2hSktGbjsEEWJOSIQAdKUihJa3ZRTLkYIlUFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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