SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac09fde29c7ec2848a4c42cb99173dd5fb7fb1f3e366d859138cc2ab63f00cb5' 
  AND token = 'KVhHunky3P5EoBuMRN2wOXjiSc105EX5ouPekdFeSno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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