SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87f93c42a1776ead37d72c758c1eeae8c0f4a8b112a6c1855a0efcc9653e50e2' 
  AND token = 'TDBTXmGY7Gh77dnVZYwLYzCoCZPhQ/HUUPu7xwZAXZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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