SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e97536316ac50ad77b319b2390b362ea1553cd4c4a251409bf34281b7d86b3f3' 
  AND token = '9mgGju6sEKsI5x0tSBgZABa+//K4s6lKRyUl36yHPzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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