SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '526837fc8e95d21433fe7b4a4b5840c5ec70344a10338f23363922ff425a9783' 
  AND token = 'hfun6899pC7rLwkxY8m0pEJPcukBJ+eX5stMdJrudOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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