SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb7e019fb05856abf388ead133f275d2f6d0f5f1cd6dd1e02de745d19b415351' 
  AND token = '2l35YTqGbJjSqFZdoLJWGrVVohyewk0qBPtSL2qzd8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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