SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37509d5bdd71a35e9138dc83570368b496335d5ff4cfc41e9a4ca70e96f6384f' 
  AND token = '9mQn9tYn2HDAyeKlsw/oJYjGGEdKe9PfZ/2pEvo642s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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