SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c5b84400634604e93b9a7fcea0ce1766101e8bb3b45f31a6659f0e32eec4bc3' 
  AND token = 'AMu0Cd0TZApr5oG1ygN6ZscbtkOzGOezNaONzAIR8A8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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