SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8737afcb6f7aa526d358d552aaba7e73dc13ad4dbbfadbc2bd4315e2a35e928' 
  AND token = 'u9MqdY/LGFJtAlW+/RjR7rmQw9uv4cjM6dypwUsuvh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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