SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70f1242a00cb2664a3ba8cb5dca3bbc9f5a30d4af038a19ea8ed1e141c684a7b' 
  AND token = 'V4yWHA+46jANOpwMmnNIq4rF3DX2bQZ/Fpk4S++m85E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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