SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92cc166d1285e014d250014c20d6dddc6ba341d7db10090cd2d4535a18d7af54' 
  AND token = 'YQ+yy7Jf0Z+EbK+lw4NWeRShgG/yBxJ2bCPHdiTmeUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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