SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '793322a114975635feff530ef09e0a250fadc75920b108d24ebda85fd79ea6ea' 
  AND token = '+8LDqkajoCV8C0l+bZCwE/0cIO/VhbhLHyBvkI4rZJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}