SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97d26adf4876bdcbd0c7feaff81be7efb188eb4da55efdf68fe810139b45c9a8' 
  AND token = 'FDmkJqwd9nnpJE/jYgLe37lJH7mnLWqRNzz4wORjrLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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