SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77114ff7921774e36619a3fcb2a1a23f1fea003ab4547c92863c19090072bcf3' 
  AND token = 'mAnCZDWGnG44PdlpAMT7pnf9pRTjgMZaJEdMBFQMwjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}