SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bef955646cfa0080b75e95756f73deb005b9930ee16919829beb7ab380403bfe' 
  AND token = 'HoptUNKDY9WQCNb/DRFylP4WB6B73tSp6E6QQ2e2yRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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