SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dbdc545fee20e1838fa3c61ead8024fa92936d18127d00f5ffafb79c4bf555e' 
  AND token = 'CV9vu5SmnH8kGYh3dJTiInfpHxJlIZdSYgnmO42JBJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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