SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8aaf13e59885342da412366be714d5ea688219347e5aec590cc35ca9089c4b41' 
  AND token = 'sgBHunbSYwJrfxoadSNLGF62EtC8FftDvZj8eCCng4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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