SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b2ae9118f2a1630ce4294f197981852f6108e380c643626468a950820e29c5f' 
  AND token = 'c/9Z9rscldThzXfonCs/0xq5zQqvC+sKWAeoChLE/dQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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